This invention relates to fluid brake control systems, and while the invention is subject to a wide range of applications, a preferred embodiment of the invention will be particularly described as applied to a fluid brake control system having an improved brake cylinder release control device.
The present invention is an improvement over currently used brake cylinder release control devices such as the brake cylinder release control device of the well-known ABD control valve generally used for governing the brakes of freight cars. In the ABD valve, a brake cylinder release control device is provided in the form of a pressure operated spool valve. This valve is costly to manufacture, requires substantial longitudinal movement to provide the selections required, and requires periodic maintenance because of wear of seals actuated across valve ports.
An object of the present invention is to provide a fluid brake control system having an improved brake cylinder release control device which substantially obviates one or more of the limitations and disadvantages of the described prior system.
Another object of the present invention is to reduce manufacturing and maintenance cost of brake application and release control devices.
Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.